6666 is nontrivially palindromic in base 10.
It is a nude number because it is divisible by every one of its digits.
6666 is a nontrivial repdigit in base 10.
It is a plaindrome in base 10.
It is a nialpdrome in base 10.
It is a zygodrome in base 10.
26666 is an apocalyptic number.
6666 is a gapful number since it is divisible by the number (66) formed by its first and last digit.
6666 is the 44-th nonagonal number.
It is a practical number, because each smaller number is the sum of distinct divisors of 6666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7344).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
6666 is a wasteful number, since it uses less digits than its factorization.
6666 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 117.
The square root of 6666 is about 81.6455755078. The cubic root of 6666 is about 18.8200931994.
The spelling of 6666 in words is "six thousand, six hundred sixty-six".